For the state of stress input, Mohr's circle is drawn and the design is marked with a + on a von Mises criterion plot.
The von Mises failure criterion is applicable to most ductile metals.

Enter the values in the units indicated in the top boxes. Where the Design Factor is to be based on the yield strength rather than the ultimate tensile strength (UTS) enter the yield strength value in the 'UTS' box.
Click on the 'Calculate' button, the principal stresses are printed in the boxes at the bottom of the cyan screen.

The 'Angle' is the rotation from the Sigma1 direction to the SigmaXX direction.

The Design Factor calculation assumes that the two principal stresses are changed by pro-rata amounts.